Egbert bbayton



g UNITED STATES PATENT OFFICE.

ROBERT BRAY'ION, OF BUFFALO, NEW YORK.

DIE.

Specification of Letters Patent No. 16,372, dated January 13, 1857.

To all whom tt muy concern:

Be it known that I, ROBERT BRAYTON, of Buffalo, in the county of Erieandl State of New York, have produced a new and useful Improvement,Consisting of Improved Dies for 'Forging and Swaging Nuts and Washers.

Figure 1 is a front elevation of the nut and washer machine described inLetters Patent granted to me Janifttry 9th, 1855. Fig. 2, isa sideelevation of the same; Fig. 3, a horizontal section in the direction ofthe line oo oo in Fig. 2; Fig. 4:, a vertical section in the directionof the line oo x', and Figs. 5, 6, 7 and 8, enlarged views of the diesdetached from the machine. The other Views, Figs. 9, 10, and 11, arealso detached sections which will be referred to in description.

Like letters denote like parts in the several views.

My invention or improvement relates to the die or dies used in machinesfor forging and swaging nuts, washers, etc., and what distinguishes myinvention from all others is the manufacturing of the die or dies forsuch or similar machines of chilled cast iron.

I do not claim to be the inventor of chilled cast iron, as that has beenknown and used for other purposes.

The machine herein represented is operated by steam, but the samearrangement of dies may be actuated by other suitable means.

The chilled cast iron dies consist of three parts or pieces A, B, C,Figs. 5, 6, 7, and 8. The die, A, works in the die boX B, and on the topof the die A, is placed a check plate D, through which and the die A,passes the punch E, as seen in Fig. 10. The die box B, is placed insidethe metallic ring F, which ring strengthens it. In this way it isattached to t-he crosshead Gr, Figs. 4; and 9. The die box B, and punchE, are so secured to the crosshead, Gr, that they move simultaneously,while the check plate D, and die A, move independently, to the extent ofthrowing the nut or other article out of the die boX B, as the crossheadascends, and as the crosshead descends and the nut is being cut off fromthe heated bar and swaged into shape the die A, and check plate D,raises the thickness of the nut. The lower die C, is so secured in placethat it will be in line with the chamber B of the die boX and with thepunch E, which enters the die C, perforating the hot blank as seen inFigs. l and 10.

In making hot pressed nuts and washers, the heated bar is placed uponthe lower die C. Then by the descent of the crosshead the blank is cutoff from the bar by the die B, and swaged and compressed into shape inthe chamber B of the die. At the same time the blank is punched by thepunch E, and the bur from the nut passing off through the hole C, in thedie C, to the ground. As the crosshead returns by the action of steamthe check plate D is brought in contact with a check bar on each side ofthe machine corresponding to H, Fig. 1. This stops the check plate D,and die A, and forces the nut out of the chamber B. Vhile the blank isbeing swaged and punched the check plate is forced against the crossheadby the die A, as seen in Fig. 1. Thus the blank is inclosed upon allsides in the chamber B, while being punched and swaged into shape. Thesides of this chamber are formed by the die box B, the top by the die A,and the bottom by the die C. In the upper die are grooves to allow thepassage of water to cool the punch as may be required, and which may bedone during the interval of heating the bar, when the machine is atrest.

The dies may be made in chill boxes, properly arranged, or by any othersuitable means, and the dies may be of other forms besides thosedescribed, so as to make nuts and washers of more or less number ofsides, as may be required. The dies heretofore in use for this purposehave been made of steel, to which there are inevitable objections. Theexpense of a set of steel dies varies from fifteen to thirty dollars,according to the size and form, while the same set of cast chilled irondies would cost from one to three dollars. The steel dies will operatewell for a short time, butas they are continually exposed to the heat ofthe hot bar and blank the steel becomes decarbonated and crystallized,and thereby so much changing the quality and nature of the steel,

by the same heat and pressure, but the die B is subject to the most heatand strain as the hot blank is swaged and punched in the die chamber B.

It is the general practice in using steel dies to cause a jet of waterto act on the dies for the purpose of cooling them, which isobjectionable, as the water in cooling the dies chills the blanks, whichblanks can not be swaged and punched as perfectly as they would be ifnot chilled. Consequently the nut is strained and hardened, or pinny,which injures the nut and the taps in cutting the thread, which is notthe case with chilled dies, as they are not affected in the same degreeby heat and pressure.

It is well known that steel when frequently subject to alternations ofheating and the action of `cold water becomes crystallized. In thisstate it is unfit for the purpose designed. By the use of steel dies theexpense of making hot nuts is rendered much greater, and they are alsomuch less perfect than those made by the use of cast chilled dies, asthe steel dies become more or less impaired in the manner herein statedand the nuts correspondingly imperfect, as the heated blank will partakeof the form and shape of the dies, as it is being punched andcompressed, for the dies forming a mold in which the hot nut is shapedany imperfection in the dies is impressed upon the nut.

The objections and difliculties consequent upon making hot nuts andwashers by the use of steel dies are not attendant upon the employmentof my improvement, as the new article produced by the chilled cast diesis better, more useful, and can be made cheaper than the old. It isfound that the peculiar nature of the chilled cast dies is such that itpartakes of all the requisite qualities of the steel dies, without theexpense, and its tendency to anneal and otherwise to be impaired by theaction of the heat and pressure in manufacturing hot nuts, like thesteel dies.

Among the advantages derived from using chilledv cast dies instead ofsteel dies the following may be enumerated: All wrought metal isnecessarily fibrous in its structure to a greater or less degree. Itsstructure therefore can not present a surface that is perfectlyhomogeneous in its character. The density of wrought steel depends uponthe cohesion of its particles by means of welding and condensation underthe hammer. The larger the mass of metal, the more imperfect will be theprocess. Tempering or rendering the surface hard depends upon the suddencooling of the mass from a red heat, in other words, a suddencrystallization of the carbonate of iron, steel being the carbonate ofiron. In thick masses this hardening extends but a little distance belowthe surface, and the temper is removed by a lower heat than thatrequired to render the mass suiciently hard for use in theprocess oftempering. In hardening steel, where large masses are concerned, it ismerely case hardening, the metal a little beneath the surface yieldingto the blow or pressure, causing the hardcned portion to crack andspalt, thus spoil* ing the dies. The outer surface also soon becomesannealed, and is thereby rendered brous. When melted cast iron issuddenly cooled, the molecular arrangement is more compact than whenleft to cool slowly, and the volume of the mass thus chilled, ascompared with steel, is greater in the ratio of the superior degree ofheat involved in the respective processes and the perfectness of theconducting medium of the mold or fluid used in the process. Themolecular arrangement of cast metal being thus more perfect, the samedegree of heat does not anneal it, and repeated blows do not render thesurface fibrous, and hence cast dies are more perfect in their structureand more durable than those constructed from wrought metal. The castchilled die is denser than the steel die and is of more extremehardness, which renders it eminently well fitted to resist the heat andintense pressure to which it is subject in the manufacture of hot nutsand other similar articles. In hardening the steel dies to render themmore durable they are liable to crack by the process, and when thustempered can not resist the same degree of heat and pressure as the castchilled iron dies, for the reason before stated. What is needed inmaking hot punched nuts and washers are dies of such eXtreme hardnessand of such strength as will best resist the heat and pressure to whichthey are subject, which are found by practical test to be chilled castdies.

What I claim as my improvement and which I desire to secure by LettersPatent is- The use of chilled cast iron die or dies, constructed andoperating substantially as leieinbefore set forth, for the purposespeci- ROBERT BRAYToN.

Witnesses:

S. D. BAUsoHAIoK, E. S. HAWLEY.

